Production of detergent alkylate



United States Patent 3,442,964 PRODUCTION OF DETERGENT ALKYLATE Wilfred John Oldham, Falkirk, Scotland, assignor, by mesne assignments, to British Hydrocarbon Chemicals Limited, London, England No Drawing. Filed Jan. 12, 1965, Ser. No. 425,059 Claims priority, application Great Britain, Jan. 17, 1964, 2,197/64 Int. Cl. C07c 3/52, 15/00, 143/24 US. Cl. 260671 19 Claims ABSTRACT OF THE DISCLOSURE Detergent alkylates are prepared by the alkylation of aromatic hydrocarbons with C C olefins. The olefins are prepared by dimerizing C -C olefins with a catalyst comprised of a synthetic petroleum cracking catalyst and a stable salt of a transition metal.

The present invention relates to the production of detergent alkylate.

The preparation of detergent alkylate fractions having an alkyl chain length of about C to C which give alkylbenzene sulphonate detergents, which can be readily metabolised by sewage bacteria, has recently assumed considera-ble importance. Hitherto, it has been thought that the use of straight chain alkylbenzenes was necessary to give biologically degradable alkylbenzene sulphonates, in contrast to the conventional highly branched-chain alkylbenzene sulphonates, derived for instance from propylene tetramer.

It has now been discovered that detergent alkylate fractions can be produced, which give biologically degradable alkylbenzene sulphonates, but which do not consist predominantly of straight chain alkylbenzenes.

According to the present invention a process for the production of detergent alkylate comprises dimerising in the liquid phase straight chain monoolefines in the C to C carbon number range in the presence of a catalyst comprising a synthetic petroleum cracking catalyst and a salt of a transition metal, which is heat stable under catalyst activation and regeneration conditions, and alkylating with a fraction of the dimerisation product in the C to C carbon number range an aromatic hydrocarbon in the presence of an alkylation catalyst.

Benzene is the preferred aromatic hydrocarbon.

The starting materials for the process of the present invention are straight chain monoolefines having carbon numbers in the range C -C The feedstock may be obtained in any suitable manner, for instance as a fraction of the products of thermally cracking a high molecular weight parafi'inic hydrocarbon, preferably after purification of the cracked fraction to remove sulphur compounds, diolefines and acetylenic hydrocarbons. Other suitable feedstocks are obtained by polymerisation of lower olefines, especially ethylene, propylene or butene and isolation of a fraction from the polymer consisting of straight chain monoolefines having 5 to 8 carbon atoms. Suitable fractions can also be made by dehydrogenation of C to C normal parafiins. In this case the olefineparaffin mixture from the dehydrogenation may be used as feedstock, and unreacted olefine and parafiin recycled in part to the dimerisation and in part to the dehydrogenation. The position of the double bond in the molecule is not critical, but the starting material. should not contain an appreciable proportion of branched chain olefines. The

presence of saturated hydrocarbons in the feedstock can be tolerated, since these do not materlally affect the dimerisation step; it is however preferred to use feedstocks not containing substantial amounts of such hydrocarbons particularly if it is desired to recycle monomeric olefine separated from the dimerisation product. Small amounts of aromatic hydrocarbons can be tolerated in the feedstock, but the proportion must be small, since these tend to form undesirable alkylated aromatics by reaction with olefine in the feed. Aromatic free feedstocks are generally to be preferred. It is preferred to operate at relatively low olefine conversion per pass, and to recycle recovered monomer, since this gives higher yields of the required detergent olefine fraction. The flow rate of ethylene may conveniently be between 0.1 and 10 volumes of liquid olefine per volume of catalyst per hour.

The catalysts which may be used in the process of the invention comprise synthetic cracking catalysts used in the cracking of petroleum and a salt of a transition metal which is heat-stable under catalyst activation and regeneration conditions. Typical examples of the cracking catalysts are silica/alumina, silica/magnesia, silica/zirconia, silica/boria, and silica/titania catalysts. The preferred cracking catalyst is silica/ alumina, suitably containing from to 90% and preferably about by weight of silica, although the proportion of silica to alumina may vary within moderately wide limits. The dimerisation catalyst may be suitably produced by impregnation of the cracking catalyst with a salt of a transition metal which does not decompose on heating with the formation of the oxide or the metal and removal of the acid radical (chloride, bromide sulphate etc.) from combination with the metal. Suitable salts include the halides and sulphates of nickel, cobalt, manganese and chromium or mixtures of any of these salts but the fluorides and iodides are less satisfactory. It is particularly preferred to impregnate the cracking catalyst with the chlorides of nickel, cobalt or manganese. The impregnation of the cracking catalyst is conveniently carried out with a solution of the transition metal salt in an ionising solvent, such as water. The catalyst is then preferably activated initially by heating in inert gas, nitrogen or air to temperatures in the range 350 to 850 C. The air or nitrogen used should be dry, and for catalysts impregnated with sulphates the use of air for activation is preferred.

Transition metal salts may be introduced into the cracking catalyst by other means than impregnation with a solution of a transition metal salt. Mixtures of transition metal sulphide and the cracking catalyst may be heated in the presence of free oxygen to oxidise the sulphide to sulphate. Thus nickel sulphate catalysts may be obtained from cracking catalyst containing nickel sulphide.

Transition metal halides may be introduced into the cracking by treating synthetic silica/ alumina cracking catalyst comprising a transition metal or a transition metal oxide with a halogenating agent. Thus nickel chloride catalysts may be prepared by heating nickel or nickel oxide containing cracking catalysts with chlorine, hydrogen chloride, or ammonium chloride.

It has been found that the incorporation of the transition metal salt increases the selectivity of the catalyst for the production of dimers. The activity of the catalyst tends to decline with long continued use, owing largely to the deposition of carbon on the catalyst surface, and may be restored in the conventional way, for instance by heating the catalyst in oxygen containing gases to temperatures in the range 300 to 600 C. However, the selectivity of the catalyst for the dimerisation reaction remains at a high level.

The required C to C olefine fraction is suitably recovered from the dimerisation product by fractional distillation, preferably under reduced pressure. The C to C olefines contained in the dimerisation product can be separated and recycled to the dimerisation step since no significant skeletal isomerisation occurs during the-dimerisation. The products of the dimerisation step are mostly olefines containing two or more branch chains, with only a small proportion of singly branched or normal olefines, such as n-dodecene. The production of biologically degradable alkylbenzene sulphonates from these products is therefore surprising.

The recovered C to C olefine fraction is condensed preferably with benzene in the presence of a suitable alkylation catalyst, such as aluminum chloride or anhydrous hydrogen fiuoride. The use of anhydrous hydrogen fluoride is preferred. The condensation is suitably carried out in the liquid phase at a temperature in the range of about 20 C. to +100 C.

The alkylation product, after separation of the catalyst, is suitably fractionated to recover unreacted benzene for recycle, a small light alkylate fraction, and a distillate detergent alkylate fraction, leaving a small residue of heavy alkylate.

Example 1 A silica-alumina cracking catalyst containing 13% by weight of alumina was heated in air at 550 C., allowed to cool and heated with an aqueous solution of nickel chloride. After standing, excess solution was removed from the solid, which was then dried in air at 80 C. to give a product containing nickel chloride equivalent to 2.4% by weight of nickel in the solid. This dried catalyst was charged to a tubular reactor, through which air was passed at 55 C. After this treatment the air was replaced with nitrogen and the catalyst allowed to cool to the reaction temperature.

A hexene feedstock containing 40% of hexene-l and 60% of hexene-Z plus hexene-3 was then pumped over the catalyst at a temperature of 80-90 C., a pressure of 400 p.s.i.g. and at a rate of 1 liquid volume per volume of catalyst per hour. The product was collected and fractionated to recover unpolymerised hexenes and a hexenefree polymer. The recovered hexenes amounted to 89.9% of the total liquid product and contained 4% of hexene-l and 96% of hexene-Z plus hexene-3. The hexene-free polymer contained 91% of C olefines, the remainder being high polymer (mainly C After this reaction the catalyst was regenerated by passing a current of air over the catalyst at 550 C., the air then being replaced by nitrogen and the catalyst cooled to reaction temperature. A hexene feedstock containing 29% of hexene-l and 71% of hexene2 plus hexene-3 was then processed over the regenerated catalyst under the same conditions as before, the product from this test containing 87.9% of unpolymerised hexenes (again containing 96% hexene-Z plus heXene-3 and 4% of hexenel) and 13.1 wt. percent of C and higher olefines, of which 91.5 percent was C olefines. The C product contained only traces of normal dodecene, less than of methylundecene, and was largely dimethyldecenes, methylethylnonenes and dimethyloctenes.

The C olefine fraction from this second test was reacted with benzene, using moles of benzene to 1 mole of olefine, with 20 moles of anhydrous hydrogen fluoride as catalyst, this alkylation reaction being carried out at 10l5 C. in the liquid phase. The HP catalyst layer was separated and the hydrocarbon layer washed with aqueous potassium hydroxide and water. After drying, the hydrocarbon product was fractionated to separate unreacted benzene, a very small light alkylate fraction, and a distillate detergent alkylate (recovered under reduced pressure) of boiling range 255-2985 C./76O mm. A small residue of heavy alkylate remained. The yield of detergent alkylate was 130 parts by weight per 100 parts of this olefine consumed, and this product was 98.3% sulphonatable. The sodium salt of the sulphonic acid derived from this detergent alkylate degraded much more rapidly and completely in biological degradation tests than the sulphonate derived from conventional tetrapropylene benzene alkylate.

Example 2 This example shows the preparation of dimer su1table for the preparation of detergent alkylate and illustrates the operation of the C dimerisation step with three different catalysts, containing nickel, manganese, and cobalt chlorides respectively. A silica-alumina cracking catalyst containing 13% of alumina which had been heated in air for 16 hours at 550 C. prior to use was employed as catalyst base. This base was impregnated with an aqueous solution of the metallic chloride as described in Example 1 to give in each case 10% by weight of the chloride on the dry catalyst. Each of the catalysts was then charged to a tubular reactor and activated by heating in a stream of nitrogen at 450 C. for 16 hours. Hexene-l was then pumped over each catalyst at a temperature of 63 C. in the liquid phase, and the product recovered and separated into unpolymerised C to C and higher polymers. The conversions and yields obtained are shown in the following table.

The C fraction of the dimerisation product was suitable for condensation with benzene in the presence of an alkylation catalyst to produce detergent alkylate.

I claim:

1. A process for production of C to C olefins having two or more branches which comprises dimerizing in the liquid phase straight chain C to C monoolefins in the presence of -a catalyst comprising a synthetic petroleum cracking catalyst and at least one salt of a transition metal, the salt being heat stable under catalyst activation and regeneration conditions, and recovering the C to C olefins formed.

2. A process as claimed in claim 1 wherein the at least one salt of a transition metal is selected from the group consisting of the halides and sulphides of nickel, cobalt, manganese and chromium.

3. A process as claimed in claim 2 wherein the salt of a transition metal is nickel chloride.

4. A process as claimed in claim 2 wherein the salt of a transition metal is manganese chloride.

5. A process as claimed in claim 2 wherein the salt of a transition metal is cobalt chloride.

6. A process as claimed in claim 1 wherein the cracking catalyst is impregnated with a salt of a transition metal by a solution of the salt in an ionising solvent.

7. A process as claimed in claim 6 wherein the cracking catalyst is impregnated with a salt of a transition metal by a solution of the salt in water.

8. A process as claimed in claim 1 wherein the cracking catalyst is selected from the group consisting of silica/ alumina, silica/magnesia, silica/zirconia and silica/boria.

9. A process as claimed in claim 1 wherein the cracking catalyst is silica/alumina containing from about -90% by weight of silica.

10. A process as claimed in claim 1 wherein the dimerisation catalyst is activated by heating in a gas selected from the group consisting of molecular oxygen containing gases and inert gases.

11. A process as claimed in claim 10 wherein the gas is air.

12. A process as claimed in claim 10 wherein the gas is nitrogen.

13. A process as claimed in claim 1 wherein the dimeri- 5 sation reaction is carried out at a temperature in the range 50 to 100 C.

14. A process as claimed in claim 1 wherein the dimerisation reaction is carried out at a pressure in the range 20 to 500 p.s.i.g.

15. A process as claimed in claim 1 wherein the olefine flow rate in the dimerisation reaction is in the range 0.1 to 10 volumes of liquid olefine per volume of catalyst per hour.

'16. In a process for the production of detergent alkylate which is biodegradable upon sulphonation, which comprises alkylating an aromatic hydrocarbon in the presence of an alkylation catalyst with an olefin and recovering the detergent alkylate formed, the improvement wherein the olefin is a C to C olefin having two or more branches produced by dimerizing in the liquid phase straight chain C to C monoolefins in the presence of a catalyst comprising a synthetic petroleum cracking catalyst and at least one salt of a transition metal, the salt being heat stable under catalyst activation and regeneration conditions.

17. In a process for the production of detergent alkylate which is biodegradable upon sulphonation, which comprises alkylating an aromatic hydrocarbon in the presence of an alkylation catalyst with an olefin and recovering the detergent alkylate formed, the improve ment wherein the olefin is a C to C olefin having two or more branches produced by dimerizing in the liquid phase straight chain C to C monoolefins in the presence of a catalyst comprising a synthetic petroleum cracking catalyst and at least one salt of a transition metal selected from the group consisting of nickel, cobalt, manganese and chromium.

18. A process for the production of a C olefin having two or more branches from a straight chain hexene feedstock which comprises dimerizing the hexene feedstock in the liquid phase in the presence of a catalyst comprising a synthetic petroleum cracking catalyst and a transition metal salt which is heat stable under catalyst activation and regeneration conditions, and recovering the formed C olefin.

-19. In a process for the production of detergent alkylate which is biodegradable upon sulphonation, which comprises alkylating an aromatic hydrocarbon in the presence of an alkylation catalyst with an olefin and recovering the detergent alkylate formed, the improvement wherein the olefin is a C olefin having two or more branches produced by dimerizing straight chain hexene feedstock in the liquid phase in the presence of a catalyst comprising a synthetic petroleum cracking catalyst and a. transition met-a1 salt which is heat stable under catalyst activation and regeneration conditions.

References Cited UNITED STATES PATENTS 3,196,174 7/1965 Cohen 260-671 XR 3,3 17,628 5/1967 Schuck et a1 260683.15 3,351,654 11/1967 Gudelis 260671 XR 2,718,526 9/1955 Mammen 260-671 X 3,109,869 11/1963 Chambers et a1. 260671 X 3,214,462 10/1965 Swenson et a1. 260671 X 3,238,249 3/1966 Mirviss et al. 260-671 X FOREIGN PATENTS 852,079 10/ 1960 Great Britain.

910,540 1 1/ 1962 Great Britain.

913,795 12/ 1962 Great Britain.

DELBERT E. GANTZ, Primary Examiner.

CURTIS R. DAVIS, Assistant Examiner.

US. Cl X.R. 260-505, 683.15 

